Interaction of aryl thiocyanates and ethylene glycol under the influence of triphenylphosphine: formation of 1,2-bis(arylthio)ethanes and of aryl 2-aryloxyethyl sulphides

Abstract

The interaction of aryl thiocyanates and 2-(arylthio)ethancls (3; R = Ar) in the presence of triphenyiphosphine appears to be a general route to 1,2-bis(arylthio)ethanes (4; R = Ar) in which the two aryl groups are notecessarily the same; likewise 2-(aryloxy)ethanols (6; R = Ar) afford a range of novel aryl 2-aryloxyethyl sulphides (7; R = Ar). Under conditions where phenyl thiocyanate with ethylene glycol and triphenylphosphine provides 2-(phenylthio) ethanol (3a), p-nitrophenyl thiocyanate gives 1,2-bis(p-nitrophenylthio)ethane (4a) directly without the intermediacy of the 2-(arylthio)ethanol (3b); p-methoxyphenyl thiocyanate with ethylene glycol gives none of the desired products. These reactions are rationalised in terms of the different modes of decomposition of the intermediate thiophosphorane ether (8).